Newman Howard, Breunig Lukas, van Zyl Gert, Stich August, Preiser Wolfgang
Division of Medical Virology, Department of Pathology, National Health Laboratory Service (NHLS), Tygerberg and Stellenbosch University, Cape Town, Western Cape, South Africa.
Division of Medical Virology, Department of Pathology, National Health Laboratory Service (NHLS), Tygerberg and Stellenbosch University, Cape Town, Western Cape, South Africa; Medical Mission Institute and University of Würzburg, Würzburg, Germany.
J Clin Virol. 2014 Aug;60(4):387-91. doi: 10.1016/j.jcv.2014.05.011. Epub 2014 May 29.
The high cost of commercial HIV-1 viral load tests for monitoring of patients on antiretroviral treatment limits their use in resource-constrained settings. Commercial genotypic antiretroviral resistance testing is even more costly, yet it provides important benefits.
We sought to determine the sensitivity and negative predictive value of a qualitative PCR targeting partial reverse transcriptase for detection of virologic failure when 5 patient specimens are pooled.
A total of 300 South African routine patient samples were included and tested in 60 pools of 5 samples each. A qualitative nested PCR was optimised for testing pools and individual samples from positive pools. All positive samples were sequenced to detect drug resistance-associated mutations. Results were compared to those of conventional viral load monitoring.
Twenty-two of 60 pools tested positive. Individual testing yielded 29 positive individual samples. Twenty-six patients had viral loads of above 1000 copies/ml. The pooling algorithm detected 24 of those 26 patients, resulting in a negative predictive value of 99.3%, and a positive predictive value of 89.7%. The sensitivity for detecting patients failing therapy was 92%, with a specificity of 98.9%. Of the patients failing first-line ART, 83.3% had NRTI and 91.7% NNRTI resistance mutations.
The pooled testing algorithm presented here required 43% fewer assays than conventional viral load testing. In addition to offering a potential cost saving over individual viral load testing, it also provided drug resistance information which is not available routinely in resourced-limited settings.
用于监测接受抗逆转录病毒治疗患者的商用HIV-1病毒载量检测成本高昂，限制了其在资源有限环境中的应用。商用基因分型抗逆转录病毒耐药性检测成本更高，但能带来重要益处。
我们试图确定当5份患者标本混合时，针对部分逆转录酶的定性PCR检测病毒学失败的敏感性和阴性预测值。
共纳入300份南非常规患者样本，分成60组，每组5份样本进行检测。对用于检测混合样本及来自阳性混合样本的单个样本的定性巢式PCR进行了优化。对所有阳性样本进行测序以检测耐药相关突变。将结果与传统病毒载量监测结果进行比较。
60组混合样本中有22组检测呈阳性。单个样本检测得到29份阳性个体样本。26名患者的病毒载量高于1000拷贝/毫升。混合检测算法检测出了这26名患者中的24名，阴性预测值为99.3%，阳性预测值为89.7%。检测治疗失败患者的敏感性为92%，特异性为98.9%。在一线抗逆转录病毒治疗失败的患者中，83.3%有核苷类逆转录酶抑制剂（NRTI）耐药突变，91.7%有非核苷类逆转录酶抑制剂（NNRTI）耐药突变。
本文提出的混合检测算法所需检测次数比传统病毒载量检测少43%。除了可能比单个病毒载量检测节省成本外，它还提供了在资源有限环境中通常无法获得的耐药信息。
